1. FIELD OF THE INVENTION
This invention relates to an ignition timing control apparatus for an internal combustion engine driving a vehicle, and more particularly to an apparatus of the kind described above which includes means for suppressing or preventing vibration of the body of the vehicle immediately after the vehicle is accelerated.
2. DESCRIPTION OF THE PRIOR ART
A prior art method of controlling the ignition timing of an internal combustion engine at the time of accelerating a vehicle is disclosed in JP-A-60-159372. According to the method disclosed therein, the ignition timing is retarded by a predetermined value from its original setting at the time of accelerating the vehicle and is then gradually restored to its original setting in accordance with the passage at every predetermined increments of time or with each ignition in the cylinder of the engine. However, the prior art method was intended to alleviate an acceleration shock occurring at the time of acceleration of the vehicle and does not consider the on longitudinal vibration of the body of the vehicle occurring after the acceleration. Selection of a large value of ignition timing retardation so as to suppress the longitudinal vibration of the vehicle body results in a loss of the feeling of acceleration or of misfiring problems, and the method has not been successful in completely preventing the undesirable longitudinal vibration of the vehicle body.
Thus, the prior art method does not consider on the longitudinal vibration of the vehicle body occurring immediately after acceleration of the vehicle and has not been satisfactory for ensuring vibration-free acceleration of the vehicle.